Horio T, Maeda S, Kishimoto N, Ohno K. Anisotropic interaction and stereoreactivity in a chemi-ionization process of OCS by collision with He*(2(3)S) metastable atoms.
J Phys Chem A 2006;
110:11010-7. [PMID:
16986833 DOI:
10.1021/jp0637781]
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Abstract
Ionic-state-resolved collision energy dependence of Penning ionization cross sections for OCS with He*(2(3)S) metastable atoms was measured in a wide collision energy range from 20 to 350 meV. Anisotropic interaction potential for the OCS-He*(2(3)S) system was obtained by comparison of the experimental data with classical trajectory simulations. It has been found that attractive potential wells around the O and S atoms are clearly different in their directions. Around the O atom, the collinear approach is preferred (the well depth is ca. 90 meV), while the perpendicular approach is favored around the S atom (the well depth is ca. 40 meV). On the basis of the optimized potential energy surface and theoretical simulations, stereo reactivity around the O and S atoms was also investigated. The results were discussed in terms of anisotropy of the potential energy surface and the electron density distribution of molecular orbitals to be ionized.
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